Android: Java 17 для Gradle (7.6.4 не тянет Java 21)

provision ставит openjdk-17, build-android.sh задаёт JAVA_HOME на
java-17 перед flutter build apk (как RustDesk CI).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

scripts/provision-android.sh

@@ -19,7 +19,8 @@ echo "[apt] deps..."
 sudo apt-get update -qq
 sudo DEBIAN_FRONTEND=noninteractive apt-get install -y -qq \
   clang libclang-dev cmake ninja-build nasm yasm pkg-config build-essential \
-  libssl-dev curl git unzip xz-utils zip python3-pip >/dev/null   # libssl-dev: host openssl-sys
+  libssl-dev openjdk-17-jdk-headless curl git unzip xz-utils zip python3-pip >/dev/null
+  # libssl-dev: host openssl-sys; openjdk-17: Gradle 7.6.4 не совместим с Java 21
 
 # --- Rust + aarch64-android ---
 if [ ! -x "$HOME/.cargo/bin/rustc" ] && ! command -v rustc >/dev/null; then